Way, way back in the day, when jocks--or, more commonly, techs and engineers--played 45s on turntables, a station engineer would literally shave some metal from the turntable spindle so the 45s played a few percent faster. (Somebody once told me as much as 10%, but that sounds a little extreme.) The physics behind it--conservation of angular momentum--is the same as that behind a skater rotating faster when she draws her arms closer to her body: make the spindle thinner, and the turntable rotates faster. The theory was--as has been stated in this thread--that a slight elevation in the pitch of the music would make the station sound brighter than its competition.